All the evidence we have suggests that human beings are adept at self-deceit. Alone among animals, humans are tellers of stories — and we tell stories to ourselves as well as to others. We trick ourselves constantly, in countless tiny ways, into believing that the bad deeds of others are very bad indeed, while our own are necessary, minor, forgivable — or maybe not even bad at all.

In one recent study, for instance, Northeastern University psychologists Piercarlo Valdesolo and David DeSteno found that when subjects were asked to assign tasks to themselves and to strangers, nearly all gave themselves easy tasks while assigning unpleasant tasks to people they didn’t know. When asked if their actions were fair, subjects were quick to find appealing rationales to justify saddling strangers with all the lousy jobs. But these same subjects were quick to condemn the same selfish behavior when they saw others engage in it.

At least on a microscopic level, then, most of us aren’t all that different from Karadzic or any of the other killers who cloaked their atrocities in the soothing rhetoric of healing. We’re all moral hypocrites, willing to believe our own justifications for the rotten things we want to do.

There’s a depressing lesson here. Uplifting rhetoric — even the language of healing, generosity and compassion — can genuinely mask the true nature of bad deeds (even from those who carry them out). As a nation at war, it’s a lesson we should remember.